Significance of prominent atrial-wave and diastasis deflection in radionuclide diastolic volume curve during exercise in detection of coronary artery disease.

Abstract

Exercise testing with multigated acquisition technetium radionuclide cineangiography (MUGA) is a useful modality that can discriminate systolic and diastolic performance in patients with ischemic heart disease. However, some patients may have abnormal left ventricular filling dynamics with normal regional and global systolic function. The purpose of the study was to assess exercise-induced diastolic dysfunction as expressed by a prominent atrial (A) wave or diastasis deflection at the left ventricular volume curve, in patients with different degrees of ischemic heart disease. In all, 32 men and 7 women aged 35-70 years (mean 54 +/- 8.6 years) underwent MUGA at rest and during exercise for analysis of the radionuclide volume curve. Within 6 weeks, thallium-201 scintigraphy and coronary angiography were performed and the patients were categorized into three groups: (1) disease-free (n = 10), (2) single-vessel disease (> 50% stenosis) (n = 19), and (3) double-vessel disease or more (n = 10). A waves or diastasis deflections were compared among the groups. Significant differences (p < 0.01) were noted in A-wave deflection relative to peak diastolic volume curve during exercise (Aexe/T) between Group 1 and Groups 2 and 3. Group 1 manifested only a mild rise in A-wave deflection from rest (20.20 +/- 8.49%) to exercise (25.85 +/- 8.49%), whereas Groups 2 and 3 exhibited a significant increase from 25.89 +/- 9.55% and 28.40 +/- 12.6%, respectively, to 60.21 +/- 22.5% and 63.0 +/- 22.86%, respectively. Group 2 had a significantly (p < 0.05) higher maximal heart rate than Group 3. The addition of prominent A-wave or diastasis deflection to a normal systolic response during exercise testing with multigated radionuclide cineangiography might be a sensitive marker of coronary artery disease. The A wave represents diastolic dysfunction of the left ventricle, considered an early event in the ischemic cascade.